Spring pin extraction means



D66. 29, 1970 J, P, 'WLLQ 3,550,241

SPRING PIN EXTRACTION MEANS Filed Sept. 26, 1968 g it 'I F/G.3 32

/4 I lav/'01:. JOSEP VILLO Q/WI ATTORNEYS United States Patent 3,550,241SPRING PIN EXTRACTION MEANS Joseph P. Villo, Rydal, Pa., assignor toStandard Pressed Steel Co., Jenkintown, Pa., a corporation ofPennsylvania Filed Sept. 26, 1968, Ser. No. 762,909 Int. Cl. 323p 19/08US. Cl. 29-229 6 Claims ABSTRACT OF THE DISCLOSURE For the removal of aspring pin from a blind hole, an internal protrusion in the spring pinand an extraction tool having a shank shaped to be inserted past theprotrusion and, after rotation of the shank, to engage the protrusion,and a nut threadedly engaging the larger diameter main body of theextraction tool so that the nut may be screwed against the outer surfaceof the member into which the spring pin is inserted to withdraw thespring pin into the nut.

This invention relates to means for extracting spring pins from blindholes.

Spring pinsthat is, longitudinally slotted cylindrical tubularmembersare used in many diverse applications, for example as wrist pins,hinge pins, pivots, assembly fasteners, stop pins, locator pins, etc. Inmany of these applications, the spring pins are inserted in blindholes-- i.e., holes open at only one end. It is frequently desired toremove the spring pins, for example, for disassembly of the mechanismfor cleaning, repair or adjustment. In blind hole installations, wherethe spring pin is fully inserted, so that it does not project beyond theouter surface of the member into which it is inserted, such removal hasproved extremely diflicult. In many instances, it has been necessary todrill out the spring pin, or to drill a hole through the member from theopposite side to permit insertion of a punch to engage the inner end ofthe spring pin so that it may be hammered out. Such expedients not onlyrequire substantial time and effort, but either destroy the Spring pinor damage the member from which it is removed.

It is therefore among the objects of the present invention to providemeans enabling quick and easy removal of a spring pin from a blind holewithout damage either to the spring pin or to the member in which it ismounted.

Another object is that of providing a spring pin extracting tool whichis simple and economical in construction and practical and convenient inoperation.

Another object is that of providing a spring pin having means engageableby an extracting tool, said means being of such nature that they may beprovided in a conventional spring pin without substantial increase ofits cost of manufacture and without preventing any normal use of thespring pin or in any way impairing its efficacy.

The spring pin shown in FIG. 1 comprises a cylindrical tube 10 having alongitudinal slot 12 therein and is provided with a pair of centrallylocated opposed indentations 14 forming in the sidewall of its bore apair of opposed internal protrustions 14'.

In FIG. 2, the spring pin is shown installed in a blind hole 16 in amember 18, with its outer end substantially flush with the adjacentouter surface 18a of the member 18. The extraction tool, generallydesignated 20, is shown in the process of being inserted into the springpin 10 preparatory to its removal from the blind hole 16.

The extraction tool 20 includes a body portion 22 which is externallythreaded, with the root diameter of the thread exceeding the outsidediameter of the spring pin. Extending coaxially from the inner end 22aof the body portion 3,550,241 Patented Dec. 29, 1970 22 is a cylindricalshank 24 whose diameter is slightly less than the inside diameter of thespring pin. The shank is provided at its inner end with a head portion26 which is provided with a pair of opposed flats 26a which are cut tosuch depth that when the tool is rotated to the inserting position shownin FIG. 2, at which these flats are opposite the internal protrusions14' in the spring pin, the head 26 will not engage the protrusionsduring insertion of the shank of the tool into the bore of the springpin. The shank is of such length that when it is fully inserted into thespring pin, as shown in FIGS. 2 and 3, the head 26 is beyond theprotrusions 14' so that the tool may be rotated to the withdrawingposition shown in FIG. 3, in which the head portion 26 is engaged behindthe protrusions 14' in position to exert a withdrawing force on thespring pin.

The head portion 26 is connected to the shank 24 by a neck portion 28which is of reduced diameter to clear the internal protrusions 14' andpermit free rotation of the tool between the aforementioned twopositions. The neck portion 28 is located so that it is opposite theprotrusions 14' when the shank is fully inserted into the spring pin 10with the inner end 22a of the body portion 22 in abutment with the outerface 18a of the member 18, so that no care is required in positioningthe neck portion opposite the protrusions 14'.

As shown in FIG. 3, a withdrawing force is exerted on the tool by a nut30 which is threaded onto the body portion 22 and against the outersurface 18a of the member 18. As the nut 30 is screwed further in thedirection of the member 18, the body portion 22 and shank 24 are drawnoutwardly, withdrawing the spring pin 10 from the hole 16, with at leastthe outer end of the spring pin moving into the bore of the nut 30,which is made possible by the fact that the crest diameter of the nutthread 32 exceeds the outside diameter of the spring pin 10.

It will therefore be appreciated that the present invention accomplishesall of the aforementioned and other apparent desirable objectives.However, it should be emphasized that the particular embodiment of theinvention described herein and shown in the drawing is intended asmerely illustrative of the principles of the invention and not asrestrictive of its scope, which is defined only by the appended claims.It will be readily apparent to those skilled in the art that variousmodifications may be made in the illustrative embodiment shown anddescribed without departing from the principles of the invention. Forexample, either a greater or a lesser number of in ternal protrusionsmay be provided in the spring pin so long as they are circumferentiallyspaced to permit insertion of the head portion of the extraction tool,which of course should be provided with at least an equal number ofsimilarly spaced relieved portions. However, a plurality ofsymmetrically spaced protrusions are preferred, so that the withdrawingforce applied to the spring pin will be balanced about the axis of thespring pin to prevent cocking of the spring pin in the hole and enableits removal from the hole within a minimum of applied force.

I claim:

1. The combination of a spring pin halving extraction means with anextraction tool engageable therewith, said spring pin comprising alongitudinally slotted cylindrical tubular body having in the sidewallof its bore a circumferentially discontinuous internal protrusion, saidextraction tool having a shank of such diameter and length as to extendinto said bore to a depth beyond said protrusion, with a head portion atthe outer end of said shank so shaped that, in one position of axialrotation of said shank, said head can move into said bore pastprotrusion and, in another position of axial rotation of said shank,said head engages said protrusion to transmit a withdrawing force tosaid spring pin, and a neck portion connecting said head portion to saidshank, said neck portion being of reduced cross section to provideclearance opposite said protrusion for axial rotation of said shankbetween said two positions.

2. The combination as described in claim 1 in which said spring pin hasa plurality of symmetrically spaced internal protrusions and the headportion of said extraction tool is provided with an equal number ofequally spaced relieved portions to clear said protrusions in certainpositions of axial rotation of said extraction tool.

3. The combination as claimed in claim 2 wherein said spring pin isprovided with two diametrically opposed internal protrusions and saidrelieved portions comprise opposed flats.

4. The combination of a spring pin having extraction means with anextraction tool engageable therewith, said spring pin comprising alongitudinally slotted cylindrical tubular body having in the sidewallof its bore a circumferentially discontinuous internal protrusion, saidextraction tool having a body portion with a shoulder thereon adapted toabut the outer surface of a member having therein a cylindrical hole inwhich said spring pin is received with its outer end substantially flushwith said outer surface, and a shank projecting perpendicularly fromsaid shoulder, the diameter and length of said shank permitting itsinsertion into said bore to a depth beyond said protrusion, with a headportion at the outer end of said shank so shaped that, in one positionof axial rotation of said shank, said head can move into said bore pastsaid protrusion and, in another position of axial rotation of saidshank, said head engages said protrusion to transmit a withdrawing forceto said spring pin, a neck portion connecting said head portion to saidshank, said neck being so located as to be opposite said protrusion whensaid shoulder is abutted with said outer surface and being of reducedcross section to provide clearance opposite said protrusion for axialrotation of said shank between said two positions.

5. The combination of a spring pin having extraction means with anextraction tool engageable therewith, said spring pin comprising alongitudinally slotted cylindrical tubular body having in the sidewallof its bore a circumferentially discontinuous internal protrusion, saidextraction tool having a shank of such diameter and length as to extendinto said bore to a depth beyond said protrusion, with a head portion atthe outer end of said shank so shaped that, in one position of axialrotation of said shank, said head can move into said bore past saidprotrusion and, in another position of axial rotation of said shank,said head engages said protrusion to transmit a withdrawing force tosaid spring pin, a neck portion connecting said head portion to saidshank, said neck portion being of reduced cross section to provideclearance opposite said protrusion for axial rotation of said shankbetween said two positions, said extraction tool also having acylindrical body portion extending axially from said shank and beingexternally threaded for threaded engagement with an internally threadednut which may be screwed onto said body and into engagement with theouter surface of a member in which said spring pin is received to exerta withdrawing force on said spring pin, with the inside diameter of saidnut exceeding the out side diameter of said spring pin to permitmovement of said spring pin into said nut as said spring pin iswithdrawn.

6. The combination of a spring pin having extraction means with anextraction tool engageable therewith, said spring pin comprising alongitudinally slotted cylindrical tubular body having in the sidewallof its bore a circumferentially discontinuous internal protrusion, saidextraction tool having a body portion with a shoulder thereon adapted toabut the outer surface of a member having therein a cylindrical hole inwhich said spring pin is received with its outer end substantially flushwith said outer surface, and a shank projecting perpendicularly fromsaid shoulder, the diameter and length of said shank permitting itsinsertion into said bore to a depth beyond said protrusion, with a headportion at the outer end of said shank so shaped that, in one positionof axial rotation of said shank, said head can move into said bore pastsaid protrusion and, in another position of axial rotation of saidshank, said head engages said protrusion to transmit a withdrawing forceto said spring pin, a neck portion connecting said head portion to saidshank, said neck being so located as to be opposite said protrusion whensaid shoulder is abutted with said outer surface and being of reducedcross section to provide clearance opposite said protrusion for axialrotation of said shank between said two positions, said body portionbeing externally threaded, and an internally threaded nut threadedlyengaging said body portion, the crest diameter of the threaded surfaceof said nut exceeding the outside diameter of said spring pin, wherebysaid nut may be screwed against said outer surface to exert awithdrawing force on said spring pin, with said spring pin movingoutwardly into said nut as said spring pin is withdrawn.

References Cited UNITED STATES PATENTS 1,536,553 5/1925 Anderson 29282X1,619,625 3/1927 Merdian 29280 2,951,282 9/1960 Albright 29-2593,125,802 3/1964 Kenin 29-427 ROBERT C. RIORDON, Primary Examiner J. C.PETERS, Assistant Examiner U.S. Cl. X.R. 29282, 427

